Occupational exposures, smoking and airway inflammation in refractory asthma - Download this document for free, or read online. Document in PDF available to download.

BMC Pulmonary Medicine

, 14:207

Asthma and allergic disorders

Abstract

BackgroundThe influence of occupation and ex-passive smoking on inflammatory phenotype is not well understood. The aim of this study was to examine the relationship between occupation, past smoking and current passive smoking and airway inflammation in a population of adults with refractory asthma.

MethodsSixty-six participants with refractory asthma were characterised. Occupational exposure to asthma causing or worsening agents were identified with an asthma-specific job exposure matrix. Exposure to passive cigarette smoke was determined by questionnaire and exhaled carbon monoxide assessment. The carbon content of macrophages was assessed in a sub-group of participants.

ResultsNineteen participants had smoked previously with low smoking pack years median 1.7 years. Ex-smokers more commonly lived with a current smoker 26% vs. 9%, p = 0.11 and were more likely to allow smoking inside their home 26% vs. 4%, p = 0.02 compared to never smokers. Twenty participants had occupations with an identified exposure risk to an asthmagen; thirteen had exposures to irritants such as motor vehicle exhaust and environmental tobacco smoke. Sputum neutrophils were elevated in participants with asthma who had occupational exposures, particularly those who were diagnosed with asthma at a more than 30 years of age.

ConclusionsSputum neutrophils are elevated in refractory asthma with exposure to occupational asthmagens. In addition to older age, exposure to both environmental and occupational particulate matter may contribute to the presence of neutrophilic asthma. This may help explain asthma heterogeneity and geographical variations in airway inflammatory phenotypes in asthma.

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